Assig-jtoe



Patented Oct. 29, 1929 UNITED STATES PATENT OFFICE JOHN E. THOMAS, OFCHICAGO, ILLINOIS, ASSIGNOR TO THE CHICAGO WHITE LEAD AND OIL 00., OFCHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS PROTECTIVE COATING NoDrawing.

This invention relates to a protective coating which, when applied overmahogany or other red aniline dye stains, prevents to a very greatextent their fading on exposure to light.

It is well known that the ordinary red stains that are applied towoodwork are not at all fast to light. Upon continued exposure to theaction of light, they fade out to a brownish shade.

It is therefore an object of this invention to provide an inexpensiveprotective coating that may be readily applied over certain stainswithout materially altering the natural color of the stains and which,when so applied will substantially prevent the stains from fading underthe action of light.

Other and further important obj ectsof this invention will be apparentfrom the disclosures in the specification and appended claims.

I have found that a preparation of various pigments, such asparanitraniline red, lithol red, toluidine red, madden lake, and others,suspended in asuitable vehicle possesses the property of rendering redaniline dye stains fast to light, when applied as a protective coatingover such stains. These pigments all have the one commoncharacteristic-a tendency to darken on exposure to light. Just whatreaction, if any, occurs between the stain and the pigments of theprotective coating is not certain. Perhaps the pigments have theproperty of absorbing those light rays that cause the fading effect.

The protective coating is prepared by grinding or mixing any one, or acombination of two or more, of the pigments named into a spirit varnish.This varnish is suitably prepared by dissolving gum shellac, Pontianak.East India, sandarac, Manila or other gum in so called spirits, by whichis meant alcohol or methylated spirits. Such a spirit varnish issuitable for use over oil'stains; but where the stain is either a wateror spirit stain. an oil varnish containing the protective pigments maypreferably be applied. The reason for this is that oil stains penetratean oil. varnish coating to give an unpleasant mottled effect, so theyrequire a spirit varnish finish.

not less than Application filed January 20, 1926. Serial No. 82,614.

But over a water or spirit stain, which will not bleed, any of the oilvarnishes into which the protective pigment has been ground or mixed ispreferable.

I have found that a preparation containing of anounce of paranitranilinered, lithol red, toluidine red, madder lake, or other pigment of similarcharacter in one gallon of spirit shellac comprised of any of the abovegums, or in one gallon of an oil varnish, produces an effectualprotective coatin'g. It is obvious that the proportion of pigment toshellac or ,varnish may be increased up to a maximum quantity determinedin part by the consistency of the mixture of shellac or varnishan'dpigment. This maximum is approximately 2 pounds of pigment to a gallon of the vehicle. In general, as the percentage of pigment in thevehicle is increased. the effectiveness of the protective coating isalso increased. but only up to a certain point.

In actual tests made bv exposing blocks of wood stained with a mahoganyaniline dye to the fading action of artificial light, it was found thatwhen the, stain was covered with mv protective coating. no appreciablefading was noticeable after ten hours of ex posure. the equivalent oftwo vears exposure under natural condit ons. W'here s during the samelength of exposure. a sample of uncoated stain faded to a light brown.It is therefore apparent that mv protective coatng is of great value insubstantiallv preventin mahoganv and red aniline stains from f ding outfrom continued exposure to the li ht.

Mv protective composition possesses the ."I'eat advantage that it mav heapplied over a s ained surface hv simnlv brushing it on in t e same wavas any varnish or shellac. hen so ap lied. the protective coating d esnot noticeab v alter the natural color of the stain. but. on thecontrary. reserves the stain in ts o i inal color against the continuedaction of s nli ht for an indefinite period.

T am aware th t many changes mavhe made and numerous details of theprocess may be aried through a wide ran e without departing from theprinci les of this invention and I therefore do not purpose limiting thepatent granted hereon otherwise than necessitated by the prior art.

I claim as my invention: 1. An article having a base coating of a redaniline dye stain and a protective coating formed thereover comprising avarnish vehicle and an organic pigment selected from a group of pigmentsconsisting of paranitraniline red, litho red, toluidine red and madderlake in a quantity sufficient to prevent fading of the red aniline stainand insufiicient to ap preciably alter the color of the stain.

2. An article having a base coating of a red aniline dye stain and aprotective coat- 15 ing formed thereover comprising a varnish vehicleand paranitraniline red in a quantity suflicient to prevent fading ofthe-red aniline stain and insufficient to appreciably alter the color ofthe stain.

20 In testimony whereof I have hereunto subscribed my name.

JOHN" E. THOMAS.

